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Biomedical subjects

Y Nishi

Publications and source records attributed to Y Nishi.

At least 163 records · Page 9Linked to original sources
PubMed1992

Human recombinant activin-A modulates the steroidogenesis of cultured bovine adrenocortical cells.

The effect of human recombinant activin-A on adrenal steroidogenesis was studied in cultured bovine adrenocortical cells. Activin-A significantly reduced cortisol output from ACTH (10nmol/l)-stimulated adrenocortical cells incubated for 24 hours in a dose-dependent manner (10, 100 and 500ng activin-A/ml suppressed cortisol secretion by 19, 33 and 40%), although no significant effect was observed in the case of 3 h incubation. Dehydroepiandrosterone (DHEA) secretion from ACTH-stimulated adrenocortical cells incubated for 24 h was also decreased by the addition of activin-A in a dose-dependent manner. (10, 100 and 500ng activin-A/ml suppressed DHEA secretion by 22, 56 and 58%). These inhibitory effects of activin-A (100ng/ml) on cortisol and DHEA secretion were partially blocked by the addition of follistatin/FSH-Suppressing Protein (200ng/ml). In contrast, activin-A treatment resulted in no significant decrease in aldosterone secretion. There were no significant effects of activin-A on basal secretions of cortisol, DHEA or aldosterone from adrenocortical cells. These results suggest that activin-A has a direct inhibitory effect on ACTH-stimulated bovine adrenocortical steroidogenesis.

Activins↗
PubMed1992

[Senile osteoporosis in normal women examination using dual energy X-ray absorptiometry].

Osteoporosis is now one of the most serious problems in aged Japanese women. We investigated bone mineral contents of the vertebrae of 132 adult women (28-94y.o.) using dual energy X-ray absorptiometry (DEXA) in order to clarify the change of the bone mineral densities (BMD) with aging, and the influences of a diet and exercise on osteoporosis. In the women, BMD of the vertebrae increase to maximum level in 3 rd or 4 th decade of life, and then reduce with aging. The level of BMD is well matched with the index of osteopenia using the lateral view of vertebral X-ray. According as the BMD reduce, the number of bone fractures and the number of patients with bone fractures increase. More than 80% of the women whose BMD are less than 0.7 g/cm2 have bone fractures. In aged women, over 65 year's old, exercise had significant positive effect with BMD, but that was no evidence for influence of calcium intake to BMD.

Absorptiometry, Photon↗
PubMed1991

Cloning and physical mapping of DNA sequences encompassing a region in N-myc amplicons of a human neuroblastoma cell line.

Cloning and physical mapping of DNA sequences encompassing N-myc amplicons of a human neuroblastoma cell line were done. A number of lambda phage clones within this region were isolated using the probes prepared by the phenol emulsion reassociation technique. Based on the restriction mapping, they were integrated into 8 contigs with sizes of 25-60 kb which, in total, encompassed a 330 kb region. Several amplicons, 100, 420, 480 and 520 kb in size as a Notl fragment, were identified using hexagonal field gel electrophoresis, and the contigs were assigned in these Notl fragments. The region encompassed by the contigs was equivalent to some 60-80% of the amplicons identified as a Notl fragment. In order to compare the amplified regions flanking the N-myc gene among the cell lines, the phage clones to cover the whole contigs were used for hybridization as a probe. The results showed that the portions of the whole contigs ranging 18-45% were also amplified in the cell lines examined. These results allowed us to identified the 'rearranged sites' which were rather evenly distributed, one at every 40 kb, through the contigs. These observations lead to the idea that an amplified DNA domain is constructed after the multiple rearrangements and then increases in number, finally resulting in the formation of subsets of amplicons with sequence homogeneity.

Cloning, Molecular↗
PubMed1991

Polyneuropathy in acute megakaryoblastic leukemia.

Peripheral neuropathy is a rare complication in leukemia. The authors report a patient with acute megakaryoblastic leukemia (AMKL) and progressive symmetric polyneuropathy. Intense infiltration of leukemic cells in a peripheral nerve was observed at autopsy. This is the first report of AMKL with peripheral nerve involvement to the knowledge of the authors.

Extremities↗
PubMed1991

Phosphorylation of keratin intermediate filaments by protein kinase C, by calmodulin-dependent protein kinase and by cAMP-dependent protein kinase.

Keratins, constituent proteins of intermediate filaments of epithelial cells, are phosphoproteins containing phosphoserine and phosphothreonine. We examined the in vitro phosphorylation of keratin filaments by cAMP-dependent protein kinase, protein kinase C and Ca2+/calmodulin-dependent protein kinase II. When rat liver keratin filaments reconstituted by type I keratin 18 (molecular mass 47 kDa; acidic type) and type II keratin 8 (molecular mass 55 kDa; basic type) in a 1:1 ratio were used as substrates, all the protein kinases phosphorylated both of the constituent proteins to a significant rate and extent, and disassembly of the keratin filament structure occurred. Kinetic analysis suggested that all these protein kinases preferentially phosphorylate keratin 8, compared to keratin 18. The amino acid residues of keratins 8 and 18 phosphorylated by cAMP-dependent protein kinase or protein kinase C were almost exclusively serine, while those phosphorylated by Ca2+/calmodulin-dependent protein kinase II were serine and threonine. Peptide mapping analysis indicated that these protein kinases phosphorylate keratins 8 and 18 in a different manner. These observations gave the way for in vivo studies of the role of phosphorylation in the reorganization of keratin filaments.

Amino Acids↗
PubMed1991

Initiating activity of eight pyrolysates of carbohydrates in a two-stage mouse skin tumorigenesis model.

Tumor initiating potential was tested for eight pyrolysates of carbohydrates in a two-stage mouse skin carcinogenesis model using 12-O-tetradecanoylphorbol-13-acetate (TPA) as the promoter. The pyrolysates were levoglucosan (LG-I), levoglucosenone (LG-II), furfural (FF), 5-(hydroxymethyl)-2-furfural (HMF), glyoxal (GL), methylglyoxal (MGL), 3-deoxy-D-glucosone (DG) and thiazolidine (TZ). The total initiating doses were 200 mumol for LG-I and DG, 25 mumol for LG-II and 500 mumol for FF, HMF, GL, MGL and TZ. 7,12-Dimethylbenz[a]anthracene (DMBA) was used as a positive control agent applied to a total dose of 100 micrograms. All compounds were topically administered to the dorsal skin twice weekly for 5 weeks with or without TPA treatment for the following 47 weeks. In conjunction with promotion TZ induced skin tumors in 40% of the mice (average 0.65 tumors/mouse), FF in 25% (0.40/mouse), LG-I in 25% (0.35/mouse) and LG-II, HMF, DG and GL in 10-20% (0.11-0.25/mouse) respectively whereas DMBA induced skin tumors in 100% of the animals (6.7/mouse). MGL did not induce any tumors during the experiment and no tumors appeared in any of the groups treated with test chemicals alone. As assessed by Fisher's exact test, tumor incidences were significant in the TZ (0.01 less than P less than 0.05) and DMBA (P less than 0.01) groups as compared with the dimethylsulfoxide (DMSO) followed by TPA groups (5%, 0.05/mouse). Statistical analyses with Peto's trend test revealed significant tumor development in the LG-I (P less than 0.01), LG-II (0.05 less than P less than 0.01), FF (0.01 less than P less than 0.05) and TZ (P less than 0.01) followed by TPA groups (compared with DMSO + TPA). The results indicate that LG-I, LG-II, FF and TZ potentially possess tumor initiating activity, while HMF, GL, MGL and DG do not, as judged by the statistical analysis based on the incidences and development of the skin papillomas and/or carcinomas. A positive correlation between tumor initiating potential and clastogenic activity based on calculated ID50 (50% initiating dose) and published CD20 (20% clastogenic dose) values was evident for LG-II, FF and TZ, while LG-I was an exception.

Animals↗
PubMed1991

Evidence for the secretion of inhibin-like immunoreactivity from cultured human adrenal cells.

We have studied the production and release of inhibin-like immunoreactivity in the human adrenal gland. Extract of human adrenal glands showed a displacement curve paralleled with the inhibin standard. Inhibin-like immunoreactivity contents in the adrenal gland was 1893 +/- 474 (mean +/- S.D.) IU/g wet weight tissue. ACTH stimulated the secretion of inhibin-like immunoreactivity as well as cortisol and aldosterone in a dose-dependent manner in the cultured adrenal cells. These results indicate that the human adrenal gland produces and secretes inhibin-like peptide in response to ACTH.

Adrenal Glands↗
PubMed1991

Rupture of pararenal pseudocyst in a patient with Down's syndrome.

A rare case of Down's syndrome with spontaneous rupture of a pararenal pseudocyst has been reported. The rupture of the pararenal pseudocyst was treated nonsurgically. The presence of this cyst in conjunction with Down's syndrome may be due, in part, to muscular hypotonia.

Down Syndrome↗
PubMed1991

[Ten years experience with the St. Jude Medical valve prosthesis for mitral valve replacement].

During the 10-year period between 1980 and December 1989, isolated mitral valve replacement (MVR) with the St. Jude Medical (SJM) valve prosthesis was performed on 404 patients at our hospital, and a long-term postoperative follow-up was conducted. There were 161 males and 243 females ranged in age from 1 year to 73 years. Early operative mortality was 5.2%. Follow-up period for 383 patients who discharged from the hospital was 1970.7 patient-years. Twenty of these patients died during the follow-up period, and a late mortality rate was 5.2%. During 10 years, thromboembolic event occurred in 8 patients. Four patients had anticoagulant-related bleeding, 4 had paravalvular leak, and 5 underwent re-operations. There was neither structural valve failure nor prosthetic valve endocarditis. Therefore, the actuarial survival rate and the valve-related death-free rate at 10 years were 83.2%, and 96.8%. Of the patients who survived, New York Heart Association class improved significantly (93% in classes II and III preoperatively and 71% in class I postoperatively). Linearized rates for thromboembolism, anticoagulant-related bleeding, and hemolysis were 0.41%, 0.20% and 0.36%/100 patient-years, respectively. The actuarial estimate of incidence free from all complications was 92.0% at 10 years. On the basis of this 10 years' experience, we believe that the SJM valve prosthesis is an excellent mechanical prosthesis for mitral valve replacement, in terms of hemodynamic performance and low thrombogenicity in patients receiving anticoagulants.

Adolescent↗
PubMed1991

[Smoking and sexual behavior of junior college students (report II). Relation to alcohol consumption and problematic behavior during adolescence].

A survey was performed on 581 junior college women regarding smoking, sexual behavior, alcohol use and problem behavior during adolescence to assess possible mutual relationships. The results are as follows: 1) Of these women, 37% experienced smoking; 9% were habitual smokers; 39% experienced kissing; 18% experienced sexual intercourse; 86% experienced alcohol drinking. 2) Many of the women had cross-experience in the combination of smoking, sexual behavior and alcohol drinking. A mutual relationship among these behaviors is suggested. 3) Many of the women who experienced smoking or sexual behavior had either experienced or considered problem behaviors during adolescence including attempted suicide, running away from home, bullying, etc. Poor adaptation to their home or school appears to be a factor associated with tendency toward smoking and sexual behavior.

Adolescent↗
PubMed1991

Inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia.

A patient with inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia (M4) is reported. He had spiking fever, epigastralgia, and elevated levels of serum C-reactive protein (CRP) and alkaline phosphatase (ALP). Ultrasonography showed a hypoechoic mass in the liver, and ultrasonically guided fine needle aspiration biopsy of the mass revealed that it was composed of fibrous connective tissue infiltrated with plasma cells, eosinophils, and neutrophils. Accordingly, a diagnosis of inflammatory pseudotumor of the liver was made. Marked reduction in the size of the lesion and a decrease of the levels of the CRP and ALP occurred without specific treatment. We emphasize the importance of ultrasonically guided aspiration biopsy in diagnosis of inflammatory pseudotumor of the liver without the need for surgery.

Biopsy, Needle↗
PubMed1991

[Coronary artery bypass grafting for ischemic heart disease combined with aortitis].

Coronary artery bypass grafting (CABG) was performed in a 67-year-old woman with aortitis. She had a past history of right radical mastectomy. Preoperative coronary angiogram showed diffuse stenotic lesions in both right and left coronary arteries. The pressure gradient between ascending aorta and peripheral radial artery was 90 mmHg and the cause of coronary stenosis seemed to be hypertension due to stenotic distal aorta. The aortogram showed occluded bilateral internal thoracic arteries (ITA) and stenotic abdominal aorta. The cephalic artery was supplied by a large meandering artery via dilated gastroepiploic artery (GEA). And thus the GEA was not useful for CABG. Quadruple CABG was performed with mild varicose saphenous vein (saphenous vein grafts to left anterior descending artery and third branch, and sequential saphenous vein graft to right posterior descending and atrioventricular branches). It seemed to be important to demonstrate the arterial lesion of ITA and GEA before CABG in patients with aortitis.

Aged↗
PubMed1990

Ca2(+)-calmodulin-dependent protein kinase II phosphorylates various types of non-epithelial intermediate filament proteins.

We have investigated the actions of Ca2(+)-calmodulin (CaM)-dependent protein kinase II on various types of non-epithelial intermediate filament proteins, vimentin, desmin, glial fibrillary acidic protein (GFAP) and neurofilament triplet proteins. Most of these filament proteins could serve as substrates. The effects of phosphorylation on the filamentous structure of vimentin were investigated in sedimentation experiments and by using electron microscopy. The amount of unassembled vimentin increased linearly with increased phosphorylation. However, the extent of the effect of phosphorylation on the potential to polymerize was also affected by the MgCl2 concentration, under conditions for reassembly. The actions of Ca2(+)-CaM-dependent protein kinase II on non-epithelial intermediate filaments under physiological conditions are given attention.

Animals↗
PubMed1990

Involvement of protein kinase C in the regulation of assembly-disassembly of neurofilaments in vitro.

Protein kinase C phosphorylated the major mammalian neurofilament protein (NF-L) with approximately 3 mol phosphate per mol protein. The phosphorylated NF-L no longer formed the filaments. Sequential analysis of the tryptic phosphopeptides, together with the known primary sequence, revealed that Ser-12, Ser-27, Ser-33 and Ser-51 were phosphorylated by protein kinase C. These findings contribute toward elucidation of mechanisms regulating the functions of neurofilaments.

Amino Acid Sequence↗
PubMed1990

Phosphorylation sites linked to glial filament disassembly in vitro locate in a non-alpha-helical head domain.

Glial fibrillary acidic protein (GFAP), the intermediate filament component of astroglial cells, can serve as an excellent substrate for both cAMP-dependent protein kinase and protein kinase C, in vitro. GFAP phosphorylated by each protein kinase does not polymerize, and the filaments that do polymerize tend to depolymerize after phosphorylation. Dephosphorylation of phospho-GFAP by phosphatase led to a recovery of the polymerization competence of GFAP. Most of the phosphorylation sites for cAMP-dependent protein kinase and protein kinase C on GFAP are the same, Ser-8, Ser-13, and Ser-34. cAMP-dependent protein kinase has one additional phosphorylation site, Thr-7. All the sites are located within the amino-terminal non-alpha-helical head domain of GFAP. These observations pave the way for in vivo studies on organization of glial filaments.

Animals↗
PubMed1990

Effect of food-restriction stress on immune response in mice.

Daily 23-h food deprivation for 1-5 days induced gastric ulcers and atrophic changes of the spleen and thymus, accompanied by a rise in plasma cortisol and catecholamine levels in mice. It also modulated several immune cell functions in the spleen including a drop in the B cell population but no change in the mitogen response of the B cells, an increase in T cell population but no change in the L3T4/Lyt2 ratio and an early increase in natural killer activity and O2- production by macrophages. These effects are thought to correlate to the increase in stress-associated humoral factors and this may partly result from stress induced by food restriction.

Animals↗